A PROCESS FOR THE PRODUCTION OF A THERMOPLASTIC ELASTOMER AND THE THERMOPLASTIC ELASTOMER

Abstract

A process for the production of a thermoplastic elastomer containing hard segments (a) of a polyester and soft segments (b) containing repeating units derived from an aliphatic carbonate, in which process a precursor thermoplastic elastomer is subjected to solid state post condensation at a temperature between 140 and 170 C. Also claimed is the thermoplastic elastomer.

Claims

1. A process for the production of a thermoplastic elastomer containing hard segments (a) of a polyester and soft segments (b) containing repeating units derived from an aliphatic carbonate, wherein in the process a precursor thermoplastic elastomer is subjected to solid state post-reaction at a temperature between 140 and 170 C.

2. A process according to claim 1, wherein the precursor thermoplastic elastomer is subjected to solid state post-reaction at a temperature below 165 C.

3. A process according to claim 1, wherein the hard segments (a) of a polyester contain as repeating units butylene terephthalate.

4. A process according to claim 1, wherein soft segments (b) contain alkylene carbonate repeating unit is represented by: ##STR00003## where RH and/or alkyl; X=2-20.

5. A process according to claim 1, wherein the hard segments (a) and the soft segments (b) are bonded via ester bonds forming copolyester units and the copolyester units are joined by a urethane group having the formula: ##STR00004## where R.sup.1=an alkyl, aryl or aralkyl group and p=2 or 3.

6. A thermoplastic elastomer containing hard segments (a) of a polyester and soft segments (b) containing repeating units derived from an aliphatic carbonate, wherein the thermoplastic elastomer has a MFI measured at 230 C. under a load of 10 kg (MFI 230 C./10 kg), according to ISO1133 (2011) of at most 40.

7. A thermoplastic polymer according to claim 6, wherein the polymer has a MFI of at most 30.

8. A polymer according to claim 6, wherein the melting temperature of the polymer measured with DSC, according to ISO 11357-1:1997 under air atmosphere (purge 50 ml/min) using a heating and cooling rate of 20 K/min is at least 180 C.

9. A polymer according to claim 8, wherein the melting temperature of the polymer is at least 200 C.

10. A thermoplastic elastomer according to claim 6, wherein the hard segments (a) of a polyester contain as repeating units butylene terephthalate.

11. A thermoplastic elastomer according to claim 6, wherein the soft segments (b) contain alkylene carbonate repeating unit is represented by: ##STR00005## where RH and/or alkyl; X=2-20.

12. A process for blow molding a polymer composition consisting of or containing the thermoplastic elastomer according to claim 6.

13. A process according to claim 12, wherein the process is suction blow molding.

14. A shaped object comprising the thermoplastic elastomer according to claim 6, wherein the shaped object is an air ducts, a corrugated tube for the production of j ounce bumpers, a cover for constant velocity joint.

Description

EXAMPLES

Materials Used:

[0034] Arnitel CM551, a copolymer containing polybutyleneterephtalate hard segments and polyhexamethylenecarbonate soft segments, having an MFI (230 C., 10 kg) of 60 g/10 min and a melting temperature of 205 C. [0035] Arnitel CM622, a copolymer containing polybutyleneterephtalate hard segments and polyhexamethylenecarbonate soft segments, having an MFI (230 C., 10 kg) of 65 g/10 min and a melting temperature of 208 C.

Test Methods:

[0036] The melting temperature was measured with DSC, according to ISO 11357-1:1997 under air atmosphere (purge 50 ml/min) using a heating and cooling rate of 20 K/min. [0037] The melt flow index (MFI) was measured according to ISO 1133 (2011).

Comparative Experiments A, B, C, D and E and Examples I and II

[0038] 25 grams of Arnitel CM622 pellets were loaded in a tubular reactor of 100 ml and heated to various temperatures under a continuous nitrogen flow of 500 grams/hour during 20 hours. The MFI and the melting temperature of the resulting material were measured. The results are given in table 1.

TABLE-US-00001 TABLE 1 Comp. Exp./ Reaction Temperature MFI Melting Temperature Example ( C.) (g/10 min) ( C.) A 80 63 205 B 110 55 204 C 130 47 203 I 150 27 203 II 170 15 199 D 180 42 190 E 190 65 180

Comparative Experiment F and Example III

[0039] 25 grams of Arnitel CM551 pellets were loaded in a tubular reactor of 100 ml and heated to various temperatures under a continuous nitrogen flow of 500 grams/hour during 16 hours. The MFI and the melting temperature of the resulting material were measured. The results are given in table 2.

TABLE-US-00002 TABLE 2 Comp. Exp./ Reaction Temperature MFI Melting Temperature Example ( C.) (g/10 min) ( C.) III 150 16 199 F 185 >200 Amorphous

[0040] At low reaction temperatures (comparative experiments A, B and C) no sufficient decrease in MFI is obtained, although no significant decrease in melting temperature is observed.

[0041] At high reaction temperatures (comparative experiments D, E and F) even an increase in MFI is observed, and a steep decrease in melting temperature is observed.

[0042] At temperatures between 140 C. and 170 C. both the significant decrease in MFI is obtained as required, while maintaining the melting temperature at an acceptable level.